Electric self-winding clock.



No. 677,8l9.

(No Model.)

0. w. THOMPSON.

ELECTRIC SELF WINDING CLOCK.

(Application filed Feb. 8, 1900.)

Patented lqiy 2, IBM.

2 Sheets-Sheet I.

Em @ov'nd \lLTiwmloson No. 677,8!9. Patented luly 2, IBM.

D. W. THOMPSON.

ELECTRIC SELF WINDING CLOCK.

(Application filed Feb. s, 1900.

2 Sheets$haet 2.

' (No Model.)

. IL LR. Q owla W .ombson H-y.

on line 2 2 of Fig. 3.

' UNITED STATES PATENT OFFICE.

DAVID \V. THOMPSON, OF CHICAGO, ILLINOIS.

ELECTRIC SELF-WINDING CLOCK.

SPECIFICATION forming part of Letters Patent N 0. 677,819, dated July 2,1901. Application filed February 8, 1900. Serial No. 3.790. (No model.)

To aid whom it may concern.-

Be it known that I, DAVID W. THOMPSON,

a citizen of the United States, residing at Chi-,

cago, in the county of Cook and State of Illinois, have invented certainnew and useful Improvements in Electric Self-Winding Clocks, of whichthe following is a specification.

This invention relates to improvements in electric self-winding clocks,and more partic ularly in those parts of such clock mechanisms whichrelate to the make-and-break contacts, which efiect the completion orinterruption of the circuit from time 'to time as the winding mechanismis brought into or cut out of action.

The object of the invention is to provide an improved construction indevices of the character referred to; and it consists in the mattershereinafter set forth, and more par ticularly pointed out in theappended claim.

In the accompanying drawings, Figure 1 is a general View, somewhatdiagrammatic in character, of parts of an electric self-winding clockmechanism constructed in accordance with-my invention, the left-handportion of the figure being in section on line 1 1 of Fig. at. Fig. 2 isa sectional detail thereof, taken Fig; 3 is a similar view taken on line3 3 of Fig. 2. Fig. 4 shows a side elevation of the principal rotaryparts. Fig. 5 is a diagrammatic view designed to more fully show theelectrical circuit. Figs. 6, 7, 8, and 9 are sectional details taken onlines correspondingly numbered in Fig. 3 for the purpose of showing theshaping of the contact wheel or disk at critical points. Fig. 10 is afragmentary perspective View of the contact wheel or disk, showing theseveral positions of the contact spring relatively thereto.

In said drawings, 1 designates the front plate of the metallic framewhich supports and contains the clock mechanism. 2 is the rear platethereof, and 3 the main shaft, which is journaled within and extendsbetween said plates in the usual manner. Secured tightly upon this shaftto rotate therewith are the hour-wheel 4 and minute-hand 5, and thehour-hand and its driving-train will be applied thereto in any usual orsuitable manner. (Not herein illustrated.) I One end of a maindriving-spring 6 is secured to the shaft 3,

while its other end is secured to a winding wheel 7, that is mounted torotate independently upon said shaft. In the operation of the clock thiswinding-wheel will be actuated from time to time to wind up thespringtiby any suitable electricallyactuated winding mechanism, theexact nature of which is not material to this invention, but which mayconveniently be made, for example, of the construction hereinillustrated. In this construction an electromagnet 8 when energized by asuitable battery 9 or other convenient source of electrical energyattracts an armaanother spring 15 beingapplied between said arm and afixed stud 16 of the clock-frame to normally maintain the armature atthatend of its throw away from the magnet. Then when the electriccircuit is completed by the means hereinafter described the armaturewill be drawn toward the magnet and will operate through the arm 11 andpawl 12 to impart to the winding-wheel a rotary impulse in adirectiontending to tighten or wind up the spring. A holding-ratchet 17, providedwith a spring 18 for maintaining it in contact with the wind Ying-wheel, serves to prevent the latter from turning backward when thecircuit is broken again, upon which event the spring 15 will restore thearmature 11 to its normal position away from the magnet ready to bedrawnup again when the latter is once more energized. The contact deviceswhich efiect the making and breaking of the circuit to accomplish suchwinding action and which embody my present invention are constructed asfollows: 19 designates a collectin g-ring, which is rigidly mount edupon the shaft 3 to rotate therewith, but is separated therefrom by aninsulating-bushing 20, and 21 is a conducting wire or brush, the freeend of which rests upon the collect ing-ring 19 and is in constantcontact therewith, no matter to what extent the shaft and ring mayrotate. This brush is connected in circuit with the magnet 8 and battery9 by a lead-wire 22, which runs from the magnet to an insulated stud 23,to which the brush 21 is secured. Adjacent to the collector-ring 19 andbetween the latter and the winding-wheel 7 is a disk or wheel 2%, ofebonite or other suit able insulatingmaterial, which is mountedtorotateon theshaft3incompanywithsaid winding-wheel and is provided onits side toward the winding-wheel with a con tact-plate 25,that

is in constant metallic contact and throughthe latter with theframe-plate 1, which frameplate is connected in circuit by a lead-wire26 with the battery 9 and magnet-8, and con-' sequently with the brush21 and collectingring 19'.

Tocomplete the circuit between the collect;

ing-ring and the contact-plate 25, I provide a contact-spring 27, whichis secured at one end to the'collecting-ring to rotate therewith andthen-after being extended outwardly beyond the periphery of the adjacentcontact-wheel 24 is doubled upon itself and its other end carried backand allowed to rest resiliently upon the periphery of saidcontact-wheel, the. tension of thespring being such as to tend to 1swing its free'or contact end 28 inwardly toward the center of the wheeland also laterally toward the collector-ring side of the wheel. I

The latter is then provided at a point adjacent to the outer end of thecontact-plate with a double or, in effect, loop-shaped path ofengagement forsaid contact end of the spring,

around which the latter travels to make and break the electricalcircuit, one portion 29 of this loop-shaped path being formed or boundedby the end of the contact-plate, which is herein shown as bent over upona flattened spot 30, provided for this purpose on the pe-J riphery ofthe wheel on one side, while the other portion of said loop shaped pathis formed by the insulating material of the wheel and, as herein shown,takes the shape of a ledge31, which gradually rises above the-end 29 ofthe contact-plate and then suddenly ter;

. minates or merges into the face 32 of a pcriphei al flange 33, thatis'provided on the opposite side of the wheel from the flattenedspot 80.The rotation of the shaft 3 and collecting-ring 19, due-to the unwindingof the. driving-spring, draws the contact end 28 of} the spring 27 alongupon the ledge 31 until. it reaches the point where the latter mergesinto the face of the flange 33, whereupon the tendency to spring inwardtoward the center of the wheel causes it to snap down drivingspring.

to draw the endof the contact-platealong beneath the contact-spring tothe rear edge of the plate, where the ledge 31 is coincident in leveltherewith, whereupon the tendency of the spring to move laterally towardthe collecting-ring will cause its end 28 to snap across the ledge andagainst the flange 33, thus breaking the circuit. The windingwheel vwillthen be held stationary by the holding-ratchet 27 until by the continuedturning of the shaft 3 the conducting-spring is drawn up the ledge againand snaps down upon the contact-plate'once more to effectanoth'erwinding impulse, and this action will be repeated as long as thecurrent supplied is of sufficient strength to move the windingwheelagainst the tension ofthe attached The loop-shaped path of movement thusprovided on the peripheryof the contact-wheel for the end 28 of thecontact-spring'needoccupy but a small portion of the circumference-ofsaid wheel, and the length or extent of eachfwinding impulse need be buta few degrees, and in the best form of the movement which I have yetconstructed isnot over about fifteen degrees, the impulses beingrepeated every two or three minutes. The effect of this system ofwinding, therefore, is to maintain the inainspring 6 under an almostconstant tension and tends greatly toward the accurate running of thetimepiece. -As a further improvement, however, and to guard against thestopping of the clockby reason of the failure of the winding mechanismto operate at any particular time a continuous path 'ofmovement for theend of the contact-spring is provided around the entire periphery of thecontact-wheel at the base or inner margin of the flange 33, so that inevent of such failure of a winding im pulse said contact-spring willsimply be drawn around the full circumference of the contact wheel untilit again rides up on the ledge 31 and snaps down on the contact-plate tocomplete the circuit. Then if the cause of the previous failure to windwas that the strength of the battery was insufficient to overcome thetension of the mainspring the lessened tension of the latter due to itshaving just unwound one full turn may enable the current toaccomplish-the winding impulse at this time. If not, the spring willsimply continue to unwind and actuate the clock and to draw thecontact-spring around the contact-wheel until the point is reached wherethe strength of the battery is sufficient to overcome the tension of themainspring and accomplish the winding. This construction, furthermore,renders it ohviously possible to set the device so that the mainspringwill operate at any desired degree of tension, which may be varied toaccommodate the load and increased as required to drive any attachmentsadded to the clock for other than time-keeping purposes. Ordinarily inpractice the spring will be wound to the least tension at which it willsafely carry its load, and since all the power of the winding mechanismis exerted directly upon the mainspring its momentum, as well as itspotential energy, will be effectively employed in the winding operation.Thus the contact may be only long enough to produce a movement of thearmature sufficient to rorate the winding-wheel the length of but twoteeth of the ratchet, for example, before the Current is cut off; butthe inertia of the armature and its connected parts will still continueto act for some time longer and may rotate the winding-wheel the lengthof two more of the ratchet-teeth, for example, before the action ceases.The spring itself thus serves to absorb the surplus energy of thebattery impulse and brings the parts to rest without jar and withoutrequiring any positive stop, and this utilization of the inertia ormomentum of the winding device makes it very easy on the battery byprolonging the interval between the windings.

Myimproved contact has no fixed time interval as measured by the train,but operates as soon as the mainspring unwinds to a predetermined point.It may fairlybe said to be located directly between the ends of saidmainspring, and its terminals revolvewith them and maintain saidmainspring at any desired tension, Varying according to the requirementsof each particular situation, always maintaining a perfectly uniformpressure uponthe train. The contact is built into the clock-movement, soas to require no adjustment, and the clock can be taken to pieceswithout disturbingit. lhe rake-off or length of contact of its terminalsis, furthermore, equal to a considerable part of an inchnearlyone-fourth of an inch in actual practice as against one or twohundredths of an inch at most, as is ordinarily common on otherclock-contacts. This obviates all tendency for the terminals to burn outand renders the use of platinum or other expensive materials unnecessaryin its construction, the parts remaining bright indefinitely when madeof the ordinary metals. Moreover, this contact device, being entirelyindependent of the other parts of the train, may be applied withoutsubstantial alteration to any kind of v movement from a mantel to atower clock.

' operated by the outer end of the mainspring,

so that the unwinding and rewinding of the mainspring directly closesand opens the electric circuit, both of said members being supportedupon and removable with said shaft and rotating in the same directionabout the axis thereof, substantially as described.

In testimony that 'I claim the foregoing as my invention 1 affix mysignature, in presence of twosnbscribing witnesses, this 30th day ofJanuary, A, D. 1900.

' DAVID w. THOMPSON.

Witnesses:

-HENRY W. CARTER,

N. R. BAILEY.

